Tamiya 70097 Twin-Motor Gearbox Kit

Tamiya’s twin-motor gearbox consists of two independent brushed DC motors and gearboxes in one compact housing, making it perfect for small robots. You can assemble the gearboxes to have a 58:1 or a 204:1 gear ratio.

Adam, who posts under the username nexisnet on the Pololu forums, has performed a detailed series of experiments to determine how operating voltage affects the lifetime of the Mabuchi FA-130 motor, which happens to be the motors used in the Tamiya 70168 Double Gearbox, 70167 Single Gearbox (4-Speed), 70097 Twin-Motor Gearbox, 70093 3-Speed Crank-Axle Gearbox, 70110 4-Speed Crank-Axle Gearbox, and 70103 Universal Gearbox.